Wrist-pin mounting for locomotive crossheads



Sept. 14, 1926. 7 1,599,740

H. G. BECKER WRIST PIN MOUNTING FOR LOCOMOTIVP CROSSHEADS Filed Sept. 30, 1924 5 Sheets-Sheet 1 @D, Fig 5e I 11v VENTOR I Haj-1y G. Bee/9a".

BY .L/ZIAM;

A TTORNEYS H. G. BECKER WRIST PIN MOUNTING FOR LOCQMGTIVE CROSSHEAD:

Filed Sept. 50, 1924 3 Sheets-Sheet 2 1 p 6 r1 0 O 4 Sept. 14, 1926. 1 599,740

WITNESSES INVENTOR B5 a'fleckefl 3 ATTORNEYS Sept. 14 1926 M. G. BECKER WRIST PIN MOUNTING FOR LOCOMOTIVE CROSSHSADS Filed Sept. 50, 19 24 3 Sheets-Sheet :3

ATTORNEYS WITNESSES Patented Sept. 14, 1926.

tll' tlTED STATES HARRY G. BECKER, OF MENAND S, NEW YORK.

WRIST-PIN MOUNTING FOR LOCGMO'IIVE CROSS'I-IEADS.

Application filed September 30, 1924. Serial No 740,786.

My invention relates to improvements in crossheads for railroad locomotives, residing more particularly in an improvement in the wrist pin by which the main drive rod is connected with the crosshead, and it consists in the constructions, combinations and arrangements herein described and claimed.

An object of the invention is to provide an improved wrist pin which may be driven in place from the outside.

Another object of the invention is to provide a wrist pin which may be applied as described, and removed from the outside with equal facility.

A further object of the invention is to provide a wrist pin which may be so fixed or locked after having once been driven into position that the loosening thereof while in operation becomes remote possibility,

Other objects and advantages will appear in the following-specification, reference be ing had to the accompanying drawings, in which:

Figure l is a perspective view illustrating the application of the improved wrist pin to a locomotive engine cross head,

Figure 2 is a plan View of the Wrist pin alone,

Figure 3 is a perspective view of thelgib,

Figure 4 is a perspective view of the key,

Figure 5 is a perspective View of the washer used in connection with the key,

Figure 6 is a longitudinal section showing the mounting of the wrist pin in the cross head, i

Figure 7 is a detail section on the line 7.7 of Figure 6,

Figure 8 is a longitudinal section of a modification of the wrist pin,

Figure 9 is a front elevation of the nodification in Figure ,8. 7

By way of preface, it may be stated that wrist pins as generally used on steam locomotives are of such a design that they must be applied from the inside ,out, and are secured in place by an arrangement of nuts and a washer on the outer and exposed end.

In applying or removing this type of wrist pin it becomes necessary to so manoeuyre the crosshead in respect to the front driver of the locomotive that the necessary clearance between spokes is obtained so that the wrist pin may ,be inserted from the inside as stated. That this is troublesome is obvious.

Engine failures and break-downs also are not uncommon upon unloosening of the nuts and the, consequent loosening and working out of the wrist pin. As the clearance between the crosshead and the side rod on the front driving wheel is very small, it can readily be seen that such working out of the wrist pin immediately results in damage.

The improved wrist pin has been designed toovercome and obviate the foregoing disadvantages. Refer to Figure 1. The cross head 1 has connection with the piston rod 2 of the locomotive so that upon being operated thereby the crosshead reciprocates on the guide 3. The crosshead includes ashoe 4 which bears ,on the guide. The main drive rod 5 is connected with the crosshead 1 by means of the wrist pin 6. The front driver 7 is operated by the side rod 8 which has connection therewith at 9 in accordance with a well known arrangement.

The crosshead includes a pronounced boss 11;) at the front or outside. It also has a boss 11 (Fig. 6) on the inside. The rosshead is so spaced between the bosses that room is made for the head 12 ofthe main drive rod 5 The purpose of the wrist pin is to furnish the necessary bearing for the inain drive rod on the cross head.

A bore 13 in the outside boss 10 communir catcs with a gib and key slot 14 which extends at right, angles thereto. The bore 13 tapers at 15, and this taper has its continuation in the tapered bore 16 of the inside boss 11.

Consider now the wrist pin 6 The front end which appears in Figure 1 is cylindrical and its in the bore 13. It merges into a frusto-conical portion 17 which fits the first taper 15. The next cylindrical portion 18 is of a lesser diameter than the cylinder 6. This portion provides the bearing with which the brasses 1 9 of the main drive rod head 12 engage. The wrist pin terminates in an even smaller frusto-conical portion 20 which fits in the last taper 16. f

This wrist pin may be driven in from the outside. It is not necessary to take precaution to have the Wrist pin come opposite a space between spokes so that it may be taken out as in the old style. The wrist pin has a slot 21 which must register with the slot 14 of the boss 10. The slot 21 is of less length in the axial direction than the slot 14. The two registering slots receive a gib 22 which is rednced at 23 to leave a pair of heels 24 to engage the slots 14 at the front.

It also has a lip 25. which limits the in sertion of the gib in the registering slots. The gib is fixed in place by a bolt 26 which extends through the bottom of the boss 10. The bolt is held in position by nuts 27 (Fig. 1). The gib is followed by the locking key 28. The inner face 29 of this key is straight and engages the inner end of the slot 21. The outer face 30 of the keytapers to correspond with the inner tapering face 31 of the gib 22. The inner face of the key does not engage the back of the slot 14 in the boss 10.

Upon hammering down on the upper end of the locking key 28 a wedge action occurs between thekey, gib and wrist pin 6, driving the latter inwardly so that the frusto-cones 17 and 20 firmly engage the complementary bores 15 and 16. The locking key is secured by nuts 32, a hollow washer 33 being first interposed. The outermost or check nut is in turn kept from running off by means of a cotter pin 34. The desired registration between the slots 14 and 21 is obtained and preserved by a key or dowel 35.

The modification in Figures 8 and 9 embodies the identical principle of the foregoing form of the invention. Similar parts are identified by numerals corresponding with those in Figure 6 but have added thereto the exponent letter a merely for the purpose of differentiating between the modification and the first form. It is not neces sary to describe these parts again.

Instead of the large cylinder 6 ending at the front of the boss 1O as in Figure 6, it merges into a stud 36 which is threaded at '37 and terminates in acircular end 38. The stud 36 receives a collar 39 which is flanged at one end at 41 and carries a Washer 40. The fixed position of the collar on the stud is insured by a dowel 42. This keeps the collar from turning.

The collar is prevented from slipping off of the stud by means of the nuts 43 which are screwed on the threaded part 37. These, in turn, areheld in place by a taper key 44 in the circular end 38. The collar 39 is for the purpose of receiving the operating rod of a valve motion. This valve motion is not illustrated because it has no bearing on the invention.

The operation may be readily understood from the foregoing description. Everyone is familiar with the reciprocating crosshead of a steam locomotive. It is the reciprocation of this crosshead that drives the wheels of the locomotive through a main drive rod 5. This drive rod is connected with the crosshead through the wrist pin 6. It is a matter of great convenience to be able to insert this wrist pin from the front because thereis very little space between the inner end of the wrist pin and the adjacent driver 7 in which to take the wrist pin out from the inside.

According to the old custom Wrist pins are so designed that they are removable from the inside, and in order to be able to do this it becomes necessary to get the cross head into such relation with the driver 7 that the wrist pin can be removed in a space between spokes. All this is unnecessary with the improved wrist pin.

Figure 6 illustrates the mounting of the wrist pin to good advantage. It is composed of two cylinders 6 and 18, of which the latter is smaller than the former. It includes the frusto-cones 17 and 20 which make a very tight fit against the complementary tapered bores 15 and 16 of the crosshead itself.

The wrist pin is first driven in with a hammer or sledge. A key 35 causes the slots 14 and 21 to register. The gib 22 is inserted in the registering slots and fixed in position by the bolt 26. The taper key 28 is next driven into the space between the back of the gib' and the slot 21.

Upon hammering down on the key the Wrist pin 6 is forced inward in respect to the boss 10 oft-the cross head so that the frusto-cones 17 and 20 engage the bosses of the crosshead very tightly.

The gib is reduced at 23 so that it forms a bridge over the wrist pin 6 at the front. The reader can understand this from Fig. 6. There must be no pressure of the gib against the wrist pin because in driving the key 28 the wrist pin must be free to move inward in a direction opposite'to the pressure against the gib. For the same reason the back of the key 28 must have clearance from the back of the slot 14.

The gib and key are equally useful in removing the wrist pin. Upon desiring to do this the gib 22 and key 28 are first removed and then reversed in position in the slots 14 and 21, and when the key 28 is driven down it acts as a buster, forcing the wrist pin from its engagements.

While the construction and arrangement of theimproved wrist pin mounting'is that of a generally, preferred form, obviously modifications and changes may be made without departing from the spirit of the invention or the scope of the claims.

I claim:

1. A crosshead having a boss with a bore and a transverse slot, a wrist pin inserted into the bore from the front of the boss and also having a slot, means by which the slots are made to register, a gib inserted through the slots at the front having a reduction to avoid the front wall of the wrist pin slot but form heels to engage the front of the boss slot, means to limit the insertion of the gib, means to fix the gib in position, a looking key having a tapered surface to engage a complementary tapering surface of the gib, and a straight surface to engage the back of the wrist pin slot but avoid the back of the boss slot, a threaded extremity on the key projecting beyond the boss when driven into position, and means locking the key in position including a washer, nuts and a cotter pin.

2. A crosshead having a boss with a bore and a transverse slot, a wrist pin fitted into the bore from the front of the boss having a slot which is not as long as the boss slot, and a gilo and a key operable in said slots to either drive the wrist pin into or out of the crosshead, both having engaging tapering faces, the gib having heels to engage the front wall of the boss slot when driving the wrist pin in or back wall of the boss slot when driving the wrist pin out, the key having a straight face to engage the back of the wrist pin slot when driving said pin in or the front of the wrist pin slot when driving said pin out.

3. A wrist pin having a cylinder, a stud formed on the said cylinder provided with a threaded portion and terminating in a cylindrical end, a flanged collar mounted on the stud, a dowel by which it is kept from turning, nuts on-the threaded portion by which the collar is held on the stud, and a key in said cylindrical end to hold the nuts.

4. A crosshead having a boss with a bore and a transverse slot, a wrist pin inserted into the bore from the front of the boss and also having a slot, means by which the slots are made to register, a gib inserted through the slots having a reduction to avoid the end walls of the wrist pin slot but form heels to engage the end walls of the boss slot when the gib is inserted in either of two positions, and a locking key having a tapered surface to engage a complementary tapering surface of the gib and a straight surface to engage the end walls of the wrist pin slot when the key is inserted in either of the two foregoing positions.

HARRY G. BECKER. 

